anv: leave the top 4Gb of the high heap VMA unused
In 628c9ca9 HIGH_HEAP_SIZE forgot to apply the same -4Gb of the high address of the high heap VMA. This was previously computed in the HIGH_HEAP_MAX_ADDRESS.
Many thanks to James for pointing this out.
Signed-off-by: Lionel Landwerlin lionel.g.landwerlin@intel.com Reported-by: Xiong, James james.xiong@intel.com Fixes: 628c9ca9 ("anv: store heap address bounds when initializing physical device")